1,2,4-Triazolo[1,5-a]pyrimidines, e.g., 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene, have been prevailingly used as a stabilizer for silver halide photographic light-sensitive materials. However, such compounds have an undesirable aspect that they tend to diffuse and move among constituent layers of the silver halide photographic light-sensitive materials to which they are added, and tend also to undergo elution into processing solutions used because they are more weakly adsorbed by silver halides than mercapto compounds such as 1-phenyl-5-mercaptotetrazole and the like. Consequently, it is difficult to stabile a specified layer alone among constituent layers of the photographic light-sensitive material using a stabilizer of this kind, and an added stabilizer will diffuse more or less into other constituent layers to exert undesirable effects on photographic characteristics of the layer which comes to contain the stabilizer (for example, to reduce the sensitivity thereof). In addition, such stabilizers have the defect that when they are dissolved into certain processing solutions and accumulated therein, they make it difficult to control the developing speed of the photographic light-sensitive materials which are processed latter, because they contribute to retarding or accelerating the progress of development. Furthermore, when such a stabilizer is added in quantities to photographic light-sensitive materials to be spectrally sensitized with dyes, it reduces the spectral sensitivities thereof.
Therefore, it is clear that it would be desirable to have 1,2,4-triazolo[1,5-a]pyrimidine series stabilizers which have properties which prevent the above-described problems.
The above desire is attained in the present invention by converting a 1,2,4-triazolo[1,5-a]pyrimidines into polymers.
It has been attempted to convert compounds known as stabilizers for silver halide photographic light-sensitive materials into polymers of units of such compounds. For instance, U.S. Pat. Nos. 3,576,638, 3,598,599 and 3,598,600 disclose polymers containing repeatedly units of a tetrazole moiety, a thiazole moiety and an imidazole moiety, respectively. However, in each of such polymers, the above-described moiety is attached to the polymer chain through its characteristic functional group (e.g., mercapto group, etc.) that is believed to make the most important contribution to the stabilizing effect in a stabilizer having a low molecular weight. Therefore, the polymer as a whole has little stabilizing effect. In addition, U.S. Pat. No. 4,134,768 describes polymers having 1-phenyl-5-mercaptotetrazole attached to the polymer chains through groups other than a mercapto group. However, such polymers are added to interlayers in the diffusion transfer process and within these layers they do not act as stabilizers but as a silver ion scavengers.
However, at present there is no known way of converting 1,2,4-triazolo[1,5-a]pyrimidines, which are most prevailingly used as the stabilizer, into polymers thereof.